function getScrollTop() {
  let scrollTop = 0,
    bodyScrollTop = 0,
    documentScrollTop = 0;
  if (document.body) {
    bodyScrollTop = document.body.scrollTop;
  }
  if (document.documentElement) {
    documentScrollTop = document.documentElement.scrollTop;
  }
  scrollTop =
    bodyScrollTop - documentScrollTop > 0 ? bodyScrollTop : documentScrollTop;
  return scrollTop;
}
function getScrollHeight() {
  let scrollHeight = 0,
    bodyScrollHeight = 0,
    documentScrollHeight = 0;
  if (document.body) {
    bodyScrollHeight = document.body.scrollHeight;
  }
  if (document.documentElement) {
    documentScrollHeight = document.documentElement.scrollHeight;
  }
  scrollHeight =
    bodyScrollHeight - documentScrollHeight > 0
      ? bodyScrollHeight
      : documentScrollHeight;
  return scrollHeight;
}

function getWindowHeight() {
  let windowHeight = 0;
  if (document.compatMode == "CSS1Compat") {
    windowHeight = document.documentElement.clientHeight;
  } else {
    windowHeight = document.body.clientHeight;
  }
  return windowHeight;
}
export function isInBottom() {
  return getScrollTop() + getWindowHeight() === getScrollHeight();
}
